Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
  • C08J2323/10—Homopolymers or copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
  • C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
  • C08L23/0815—Copolymers of ethene with aliphatic 1-olefins

Definitions

• the invention relates to a propylene composition, its production process, an article made therefrom and the use of the polypropylene composition in various applications, especially blown films.
• polyethylenes are replaced by polypropylenes since the new generation of polypropylenes has superior properties compared to customary polyethylene materials.
• polypropylenes of commerce are particularly isotactic, semicrystalline, thermoplastic polymer mixtures.
• the polypropylenes of commerce have many desirable and beneficial properties, like heat resistance and high stiffness, they also possess some important drawbacks such as high viscosity, which results in a reduced throughput in many applications, such as for blown films, extrusion coating, foam extrusion and blow-molding.
• high viscosity which results in a reduced throughput in many applications, such as for blown films, extrusion coating, foam extrusion and blow-molding.
• a high stiffness can result in the creation of wrinkles on the film reel as the lay flattening of high stiffness materials is very critical.
• EP 1 847 555 describes propylene homo- and copolymers being multibranched, i.e. the polypropylene backbone is furnished with a larger number of side chains (branches) and said branches contain further side chains.
• the melt of these polypropylenes has a high strength the throughput for applications like blown films, extrusion coating, foam extrusion, blow-molding etc. can still be improved.
• Polypropylenes usually can only be processed with reduced throughput e.g. when producing blown films, in extrusion coating, in foam extrusion and in blow-molding. Blending with high pressure LDPE containing long chain branches usually improves the processability, however, the stiffness and heat resistance decreases.
• the object of the present invention can be achieved with a polypropylene composition which comprises a base resin consisting of two different propylene homo- or copolymers (A) & (B) and a linear low density ethylene homo- or copolymer (C) which has been produced with a single-site catalyst.
• the present invention provides a polypropylene composition
• a base resin consisting of
• the inventive composition is characterized by good heat resistance, high stiffness and it can be processed with increased throughput. Further, the composition shows good optical properties.
• high pressure LDPE containing long chain branches is used to improve the processability of polypropylenes, especially on blown film lines.
• conventional high pressure LDPE does not or only negligible improve the processability of the mixture of the polypropylene components (A) and (B) of the inventive composition.
• LLDPE which has been produced with a single-site catalyst is usually difficult to process due to its low molecular weight and very narrow molecular weight distribution (MWD).
• MLDPE molecular weight distribution
• polyolefin denotes an olefin homo- or copolymer or a mixture of such olefin homo- or copolymers.
• polypropylene denotes a propylene homo- or copolymer or a mixture of such propylene homo- or copolymers.
• polyethylene denotes an ethylene homo- or copolymer or a mixture of such ethylene homo- or copolymers.
• propylene copolymer includes propylene homopolymers, propylene random copolymers as well as heterophasic propylene copolymers, i . e . a mixture of a propylene homo- or random copolymer with a propylene/alpha-olefin rubber as well as mixtures of propylene homopolymer, random copolymers and heterophasic propylene copolymers.
• Multimodal or “multimodal distribution” describes a probability distribution that has several relative maxima.
• the expression “modality of a polymer” refers to the form of its molecular weight distribution (MWD) curve, i.e. the appearance of the graph of the polymer weight fraction as a function of its molecular weight. If the polymer is produced in the sequential step process, i.e. by utilizing reactors coupled in series, and using different conditions in each reactor, the different polymer fractions produced in the different reactors each have their own molecular weight distribution which may considerably differ from one another.
• the molecular weight distribution curve of the resulting final polymer can be calculated by a super-imposing of the molecular weight distribution curves of the polymer fraction which will, accordingly, show a more distinct maxima, or at least be distinctively broadened compared with the curves for individual fractions.
• a polymer showing such molecular weight distribution curve is called bimodal or multimodal, respectively.
• the amount of component (A) is at least 55 wt.%, more preferably at least 60 wt.%, even more preferably is at least 65 wt.% and most preferably is at least 70 wt.% of the base resin.
• the amount of component (A) is not more than 95 wt.%, more preferably is not more than 90 wt.% of the base resin.
• the amount of component (B) is at least 2.5 wt.%, more preferably is at least 5.0 wt.% and most preferably is at least 7.5 wt.% of the base resin.
• the amount of component (B) is not more than 20.0 wt. %, more preferably is not more than 15.0 wt.% and most preferably is not more than 12.5 wt.% of the base resin.
• the amount of component (C) is up to 25.0 wt.%, more preferably is up to 20.0 wt.% and most preferably is up to 17.5 wt.% of the base resin.
• the amount of component (C) is at least 1.0 wt.%, more preferably is at least 2.5 wt.% of the base resin.
• the sum of components (A) and (C) is at least 70 wt.%, more preferably at least 80 wt.% and most preferably at least 85 wt.% based on the polypropylene composition.
• the sum of components (A) and (C) is not more than 97.5 %, more preferably not more than 95.0 wt.% and most preferably not more than 92.5 wt.% based on the polypropylene composition.
• the amount of the base resin is at least 80 wt. %, more preferably at least 85 wt.%, even more preferably at least 90 wt.% and most preferably at least 95 wt.% of the polypropylene composition.
• Component (A) is a propylene homo- or copolymer.
• component (A) has an intrinsic viscosity (IV) of not more than 4.5 dl/g, more preferably of not more than 4.0 dl/g and most preferably of not more than 3.5 dl/g.
• component (A) has an intrinsic viscosity (IV) of at least 1.2 dl/g, more preferably of at least 1.5 dl/g, even more preferably of at least 1.8 dl/g and most preferably of at least 2.0 dl/g.
• component (A) has an MFR 2 measured according to ISO 1133, at 230°C and under a load of 2.16 kg, of at least 0.01 g/10 min, more preferably of at least 0.1 g/10 min, even more preferably of at least 0.5 g/10 min, even more preferably of at least 1.0 g/10 min and most preferably of at least 1.5 g/10 min.
• component (A) has an MFR 2 measured according to ISO 1133, at 230°C and under a load of 2.16 kg, of not more than 20.0 g/10 min, more preferably of not more than 10.0 g/10 min and most preferably of not more than 5.0 g/10 min.
• component (A) has a density of at least 850 kg/m 3 , more preferably of at least 875 kg/m 3 and most preferably of at least 900 kg/m 3 .
• component (A) has a density of not more than 950 kg/m 3 , more preferably not more than 925 kg/m 3 and most preferably of not more than 910 kg/m 3 .
• component (A) has a melting point of at least 140°C, more preferably of at least 150°C and most preferably of at least 160°C.
• component (A) is a propylene copolymer.
• said propylene copolymer has a comonomer content of not more than 10.0 wt.%, more preferably of not more than 7.5 wt.% and most preferably of not more than 5.0 wt.% based on component (A).
• said propylene copolymer has a comonomer content of at least 1.0 wt.%, more preferably of at least 1.5 wt.% and most preferably of at least 2.0 wt.% based on component (A).
• component (A) has an impact strength at 23°C of at least 25 kJ/m 2 , more preferably of at least 30 kJ/m 2 in a Charpy notched test according to ISO 179-1 eA:2000.
• the comonomers used for the production of component (A) may be selected from but are not limited to ethylene and/or C 4 - to C 20 -alpha-olefins.
• ethylene and/or C 4 - to C 20 -alpha-olefins are preferred, even more preferred are ethylene and/or C 4 - to C 15 -alpha-olefins, even more preferred are ethylene and/or C 4 - to C 10 -alpha-olefins and most preferred are ethylene and/or C 4 - to C 6 -alpha-olefins.
• the component (A) is alpha-nucleated with a nucleating agent.
• a nucleating agent e.g., a nucleating agent for a nucleating agent for a nucleating agent for a nucleating agent for a nucleating agent for a nucleating agent for a nucleating agent for a nucleating agent for a nucleating agent for a nucleating agent for a nucleating agent for the alpha-nucleation.
• the alpha-nucleating agent if present, is preferably selected from the group consisting of sodium benzoate, 1,3:2,4-bis-(3,4-dimethyl-benzylidene)-sorbitol, sodium-2,2'-methylenebis-(4,6-di-tert-butyl-phenyl)-phosphate, hydroxybis-(2,4,8,10-tetra-tert-butyl-6-hydroxy-12h-dibenzo-(d,g)(1,3,2)-dioxaphosphocin-oxidato)-aluminium, ADK STAB NA-21 (Adeka Palmarole, France), Hyperform HPN-20 E (Milliken, USA) or mixtures thereof.
• a further and preferred alpha-nucleation method is a special reactor technique, where the catalyst is prepolymerized with at least one vinyl compound, said method is herein later referred to as "BNT".
• This method is described in detail in EP 1 028 984 and EP 1 183 307 .
• "BNT” is referred to as alpha-nucleating agent.
• Preferred vinyl compounds to be used in the Borstar Nucleation Technology (BNT)-method are represented by the following formula wherein R 1 and R 2 are independently selected from C 1 -C 4 -alkyl groups or they form together a saturated, an unsaturated or an aromatic five- or six-membered ring, whereby this ring may be substituted and/or bridged with one or more C 1 - or C 2 -alkyl groups.
• the vinyl compound is selected from vinyl cycloalkanes, e.g. vinyl cyclopentane, vinyl cyclohexane, vinyl-2-methyl-cyclohexane and vinyl norbonane, 3-methyl-1-butene, styrene, p-methyl-styrene, 3-ethyl-1-hexene or mixtures thereof, particularly preferred is vinyl cyclohexane (VCH).
• vinyl cycloalkanes e.g. vinyl cyclopentane, vinyl cyclohexane, vinyl-2-methyl-cyclohexane and vinyl norbonane, 3-methyl-1-butene, styrene, p-methyl-styrene, 3-ethyl-1-hexene or mixtures thereof, particularly preferred is vinyl cyclohexane (VCH).
• the catalyst is prepolymerised in the BNT method at a temperature significantly below the polymerization temperature.
• said prepolymer fraction is preferably present in an amount of up to 1.0 wt. %, more preferably up to 0.5 wt. % and most preferably up to 0.2 wt. % based on component (A).
• said prepolymer fraction is preferably present in an amount of at least 0.0001 wt. %, more preferably of at least 0.001 wt. %, even more preferably of at least 0.005 wt. %, and most preferably of at least 0.01 wt.% based on component (A).
• component (A) is a heterophasic propylene copolymer (AA) comprising
• component (A0), if present, has been prepolymerised with the BNT-method as described above.
• component (A1) and (A2) and, if present, component (A0) make up at least 98.0 wt.%, more preferably at least 99.0 wt. % and most preferably at least 99.5 wt.% of component (AA) and most preferably component (AA) consists of components (A1), (A2) and (A0)
• component (A0) is present in component (AA), preferably, the amount of component (A0) is up to 1.0 wt. %, more preferably up to 0.5 wt. % and most preferably up to 0.2 wt. % based on component (AA).
• component (A0) is present in component (AA), preferably, the amount of component (A0) is at least 0.0001 wt. %, more preferably is at least 0.001 wt. %, even more preferably is at least 0.005 wt. %, and most preferably is at least 0.01 wt.% based on component (AA).
• component (A1) has a comonomer content of not more than 10 wt.% based on component (A1), more preferably of not more than 5 wt.% based on component (A1), even more preferably of not more than 2 wt.% based on component (A1) and most preferably component (A1) is a propylene homopolymer.
• component (A1) has an MFR 2 , measured according to ISO 1133 at 230°C and under a load of 2.16 kg, of at least 0.5 g/10 min, more preferably of at least 1.0 g/10 min and most preferably of at least 1.5 g/10 min.
• component (A1) has an MFR 2 , measured according to ISO 1133 at 230°C and under a load of 2.16 kg, of not more than 30 g/10 min, more preferably of not more than 20 g/10 min and most preferably of not more than 10 g/10 min.
• component (A1) is present in an amount of at least 75.0 wt.%, more preferably of at least 80.0 wt.% and most preferably of at least 82.5 wt.% based on component (AA).
• component (A1) is present in an amount of not more than 95.0 wt.%, more preferably of not more than 92.5 wt.% and most preferably of not more than 90.0 wt.% based on component (AA).
• component (A1) has an intrinsic viscosity (IV) of not more than 4.5 dl/g, more preferably of not more than 4.0 dl/g and most preferably of not more than 3.5 dl/g.
• component (A1) has an intrinsic viscosity (IV) of at least 1.5 dl/g, more preferably of at least 1.8 dl/g and most preferably of at least 2.0 dl/g.
• the comonomers used for the production of component (A2) may be selected from but are not limited to ethylene and/or C 4 - to C 20 -alpha-olefins.
• ethylene and/or C 4 - to C 20 -alpha-olefins are preferred, even more preferred are ethylene and/or C 4 - to C 15 -alpha-olefins, even more preferred are ethylene and/or C 4 - to C 10 -alpha-olefins, e.g. ethylene, 1-butene, 1-hexene, 1-octene, and most preferably the alpha-olefin is ethylene.
• component (A2) has a comonomer content of not more than 50 wt.%, more preferably of not more than 45 wt.% and most preferably of not more than 40 wt.% based on component (A2).
• component (A2) has a comonomer content of at least 15 wt.%, more preferably of at least 20 wt.% based on component (A2).
• the amount of component (A2), determined as xylene solubles (XS), is not more than 25.0 wt.%, more preferably not more than 20.0 wt.% and most preferably not more than 17.5 wt.% based on component (AA).
• the amount of component (A2), determined as xylene solubles (XS), is at least 5.0 wt.%, more preferably is at least 7.5 wt.% and most preferably is at least 10 wt.% based on component (AA).
• the intrinsic viscosity (IV) of component (A2) is at least 0.8 dl/g, more preferably is at least 1.0 dl/g, and most preferably is at least 1.2 dl/g, component (A2) being measured as xylene soluble fraction as described above.
• the intrinsic viscosity (IV) of component (A2) is not more than 2.5 dl/g, more preferably is not more than 2.3 dl/g and most preferably is not more than 2.1 dl/g, component (A2) being measured as xylene soluble fraction as described above.
• the ratio IV(A2)/)V(A1) is not higher than 0.85 and more preferably not higher than 0.80.
• component (A2) is dispersed within the component (A1), or if component (A0) is present, in the mixture of components (A1) and (A0), preferably in the form of particles, more preferably said particles have a weight average particle size of less than 1.00 ⁇ m, more preferably less than 0.50 ⁇ m; further, preferably, said particles have a weight average particle size of at least 0.05 ⁇ m, more preferably of at least 0.10 ⁇ m.
• slurry reactor designates any reactor, such as a continuous or simple batch stirred tank reactor or loop reactor, operating in bulk or slurry and in which the polymer forms in particulate form.
• Bok means a polymerization in reaction medium that comprises at least 60 wt.-% monomer.
• the slurry reactor comprises (is) a bulk loop reactor.
• gas phase reactor is meant any mechanically mixed or fluid bed reactor.
• the gas phase reactor comprises a mechanically agitated fluid bed reactor with gas velocities of at least 0.2 m/sec.
• the polymerization reactor system used for the production of component (A) can comprise one or more conventional stirred tank slurry reactors or loop reactors, as described in WO 94/26794 , and/or one or more gas phase reactors.
• the reactors used for the production of component (A) are selected from the group of loop and gas phase reactors and, in particular, the process employs at least one loop reactor and at least one gas phase reactor.
• component (A) is a heterophasic propylene copolymer (AA)
• component (A1) is produced in at least one loop reactor and component (A2) is produced in at least one gas phase reactor.
• a suitable catalyst for the polymerization of component (A) is any stereospecific catalyst for propylene polymerization which is capable of polymerizing and copolymerizing propylene and comonomers at a temperature of 40 to 110 °C and at a pressure from 10 to 100 bar.
• Ziegler Natta catalysts as well as metallocene catalysts are suitable catalysts.
• the catalyst is preferably introduced into the first reactor only.
• the components of the catalyst can be fed into the reactor separately or simultaneously or the components of the catalyst system can be precontacted prior to the reactor.
• a suitable propylene composition usable as component (A) and the process for its production is described in EP 1 661 935 .
• Component (B) is a propylene homo- or random copolymer with a comonomer content of not more than 5 wt.% and a branching index g' of less than 0.9.
• component (B) has an MFR 2 measured according to ISO 1133, at 230°C and under a load of 2.16 kg, of at least 0.01 g/10 min, more preferably of at least 0.2 g/10 min, even more preferably of at least 1.0 g/10 min, even more preferably of at least 2.0 g/10 min and most preferably of at least 4.0 g/10 min.
• component (B) has an MFR 2 measured according to ISO 1133, at 230°C and under a load of 2.16 kg, of not more than 1000 g/10 min, even more preferably of not more than 100 g/10 min more preferably of not more than 50 g/10 min, even more preferably of not more than 25 g/10 min and most preferably of not more than 10.0 g/10 min.
• the cross-linked fraction of the polypropylene (B) does not exceed 1.0wt.-%, even more preferred does not exceed 0.8wt.-%, still more preferred does not exceed 0.5 wt.-% determined as the relative amount of polymer insoluble in boiling xylene (xylene hot insoluble fraction, XHI).
• component (B) has a density of at least 850 kg/m 3 , more preferably of at least 875 kg/m 3 and most preferably of at least 900 kg/m 3 .
• component (B) has a density of not more than 950 kg/m 3 , more preferably of not more than 925 kg/m 3 and most preferably of not more than 910 kg/m 3 .
• component (B) has a melting point of at least 140°C, more preferably of at least 150°C and most preferably of at least 160°C.
• component (B) has a pentade concentration, of more than 90 %, more preferably of more than 92 % , even more preferably of more than 93 % and most preferably of more than 95 %.
• the pentade concentration is an indicator for the narrowness in the regularity distribution of the polypropylene.
• component (B) has a melt strength of at least 5.0 cN at a maximum speed of at least 100 mm/s, more preferably of at least 10 cN at a maximum speed of at least 200 mm/s.
• the measuring of the melt strength has been undertaken by a temperature of 200 °C with an acceleration of the melt strand drawn down of 120 mm/s 2 .
• the exact measuring method is defined in the example section.
• the high melt strength is preferably achieved by a certain degree of branching of the propylene polymer.
• a parameter of the degree of branching is the branching index g'.
• the branching index g' correlates with the amount of branches of a polymer.
• a low g'-value is an indicator for a high branched polymer.
• the intrinsic viscosity needed for determining the branching index g' is measured according to DIN ISO 1628/1, October 1999 (in Decalin at 135 °C).
• the branching index g' of the polypropylene (B) is less than 0.90, more preferably not more than 0.80, more preferably not more than 0.70.
• Polypropylenes of type a) and b) are for instance described in EP 0 787 750
• polypropylenes of type c) are described in EP 1 903 070 .
• the homopolymer can be unimodal or multimodal. In case the homopolymer is multimodal, it is preferably bimodal.
• component (B) is a random copolymer any comonomers used for the production of random copolymers known in the art may be used, however, ethylene and/or C 4 - to C 20 -alpha-olefins are preferred, even more preferred are ethylene and/or C 4 - to C 15 -alpha-olefins, even more preferred are ethylene and/or C 4 - to C 10 -alpha-olefins, even more preferred are ethylene and/or C 4 - to C 6 -alpha-olefins, and most preferred is 1-hexene.
• the random copolymer has a comonomer content of not more than 5.0 wt. %, preferably of not more than 4.0 wt.% and more preferably of not more than 3.0 wt.%.
• the random copolymer has a comonomer content of at least 1.0 wt.%, more preferably of at least 1.5 wt.%.
• the random copolymer can be unimodal or multimodal. In case the random copolymer is multimodal, it is preferably bimodal.
• component (B) is a propylene homopolymer.
• component (B) Any process for the production of polypropylenes which is known in the art may be used for the production of component (B).
• the process temperature is higher than 60 °C.
• the process is a multi-stage process to obtain a multimodal polypropylene as defined above.
• Multistage processes include also bulk/gas phase reactors known as multizone gas phase reactors for producing multimodal propylene polymer.
• a preferred multistage process is a "loop-gas phase"-process, such as developed by Borealis A/S, Denmark (known as BORSTAR® technology) described e.g. in patent literature, such as in EP 0 887 379 or in WO 92/12182 .
• Multimodal polymers can be produced according to several processes which are described, e.g. in WO 92/12182 , EP 0 887 379 and WO 97/22633 .
• a multimodal polypropylene according to this invention is produced preferably in a multi-stage process in a multi-stage reaction sequence as described in WO 92/12182 .
• the main polymerization stages are preferably carried out as a combination of a bulk polymerization/gas phase polymerization.
• the bulk polymerizations are preferably performed in a so-called loop reactor.
• the composition be produced in two main polymerization stages in combination of loop reactor/gas phase reactor.
• the process may also comprise a prepolymerization step as defined above and which may precede the polymerization step (a).
• the process is preferably a continuous process.
• the conditions for the bulk reactor of step (a) may be as follows:
• step a) the reaction mixture from the bulk (bulk) reactor (step a) is transferred to the gas phase reactor, i.e. to step (b), whereby the conditions in step (b) are preferably as follows:
• the residence time can vary in both reactor zones.
• the residence time in bulk reactor, e.g. loop is in the range 0.5 to 5 hours, e.g. 0.5 to 2 hours and the residence time in gas phase reactor will generally be 1 to 8 hours.
• the polymerization may be effected in a known manner under supercritical conditions in the bulk, preferably loop reactor, and/or as a condensed mode in the gas phase reactor.
• a polypropylene suitable as component (B) can be obtained as described in the following.
• the polypropylene (B) can be the result of treating an unmodified polypropylene (B') with thermally decomposing radical-forming agents and/or with ionizing radiation, where both treatments may optionally be accompanied or followed by a treatment with bi- or multifunctionally unsaturated monomers, e.g. butadiene, isoprene, dimethylbutadiene or divinylbenzene.
• a suitable method to obtain the polypropylene (B) is for instance disclosed in EP 0 879 830 A1 and EP0890612A2 .
• the unmodified polypropylene (B') has preferably an MFR 2 (230°C) in a range of 0.05 to 45.00 g/10 min. More preferably the MFR 2 (230°C) is in a range of 0.05 to 35.00 g/10 min in case the unmodified polypropylene (B') is a homopolymer. On the other hand the MFR 2 (230 °C) is in a range of 0.05 to 45.00 g/10 min in case the unmodified polypropylene (B') is a copolymer.
• the unmodified polypropylene (B') has a comonomer content from 0.1 to 15.0wt.% of ethylene and or C 4 - to C 18 - alpha-olefins, in particular ethylene.
• unmodified polypropylene (B') has preferably a rather broad molecular weight distribution (MWD), more preferably the unmodified polypropylene (B') is multimodal, even more preferably bimodal.
• MWD molecular weight distribution
• the unmodified polypropylene (B') has preferably a weight average molecular weight (M w ) of 500,000 to 1,500,000 g/mol, more preferably in the range of 600,000 to 1,000,000 g/mol.
• M w weight average molecular weight
• M n number average molecular weight
• the peroxide used for the manufacture of polypropylene (B) is preferably a thermally decomposing free radical-forming agent, more preferably selected from the group consisting of acyl peroxide, alkyl peroxide, hydroperoxide, perester and peroxycarbonate.
• the (volatile) bifunctional monomers are preferably ethylenically unsaturated, multifunctional monomers, like C 4 - to C 10 - dienes and/or C 7 - to C 10 - divinyl compounds.
• Especially preferred bifunctional monomers are butadiene, isoprene, dimethylbutadiene and divinylbenzene.
• the polypropylene (B) is preferably obtained by a process as described in EP 0 879 830 A1 and EP 0 890 612 A2 . Accordingly the polypropylene is produced by
• auxiliary substances which may range from 0.01 to 2.5% by weight of stabilizers, 0.01 to 1% by weight of processing aids, 0.1 to 1% by weight of antistats, 0.2 to 3% by weight of pigments and up to 3% by weight of ⁇ -nucleating agents, in each case based on the sum of the propylene polymers, may be added before step a) and/or f) of the method and/or before or during step d) and/or e) of the above described method.
• the process for producing the modified propylene polymer preferably is a continuous method, performed in continuous reactors, mixers, kneaders and extruders. Batchwise production of the modified propylene polymer however is feasible as well.
• the sorption times ⁇ is from 10 to 1000 s, more preferably ⁇ is from 60 to 600.
• Polypropylene (B) can also be produced in the presence of a metallocene catalyst, as, for example, described in EP 1 892 264 using a catalyst system comprising an asymmetric catalyst, whereby the catalyst system has a porosity of less than 1.40 ml/g, more preferably less than 1.30 ml/g and most preferably less than 1.00 ml/g.
• the porosity has been measured according to DIN 66135 (N 2 ). In another preferred embodiment the porosity is not detectable when determined with the method applied according to DIN 66135 (N 2 ).
• An asymmetric catalyst is a metallocene compound comprising at least two organic ligands which differ in their chemical structure. More preferably the asymmetric catalyst is a metallocene compound comprising at least two organic ligands which differ in their chemical structure and the metallocene compound is free of C 2 -symmetry and/or any higher symmetry. Preferably the asymmetric metallocene compound comprises only two different organic ligands, still more preferably comprises only two organic ligands which are different and linked via a bridge.
• Said asymmetric catalyst is preferably a single site catalyst (SSC).
• SSC single site catalyst
• the catalyst system has a surface area of less than 25 m 2 /g, yet more preferred less than 20 m 2 /g, still more preferred less than 15 m 2 /g, yet still less than 10 m 2 /g and most preferred less than 5 m 2 /g.
• the surface area according to this invention is measured according to ISO 9277 (N 2 ).
• the catalytic system comprises an asymmetric catalyst, i.e. a catalyst as defined below, and has porosity not detectable when applying the method according to DIN 66135 (N 2 ) and has a surface area measured according to ISO 9277 (N 2 ) less than 5 m 2 /g.
• the asymmetric catalyst compound i.e. the asymmetric metallocene
• Cp is an organic ligand selected from the group consisting of unsubstituted cyclopentadienyl, unsubstituted indenyl, unsubstituted tetrahydroindenyl, unsubstituted fluorenyl, substituted cyclopentadienyl, substituted indenyl, substituted tetrahydroindenyl, and substituted fluorenyl, with the proviso that both Cp-ligands are selected from the above stated group and both Cp-ligands have a different chemical structure
• ⁇ -ligand is understood in the whole description in a known manner, i.e. a group bonded to the metal at one or more places via a sigma bond.
• Preferred monovalent anionic ligands are halogenes, in particular chlorine (Cl).
• the asymmetric catalyst is of formula (I) indicated above, wherein M is Zr and each X is Cl.
• both Cp-ligands are selected from one of the groups of substituted cyclopentadienyl, substituted indenyl, substituted tetrahydroindenyl, and substituted fluorenyl and wherein the Cp-ligands differ in the substituents bonded to the rings to obtain an asymmetric structure.
• the optional one or more substituent(s) bonded to cyclopentadienyl, indenyl, tetrahydroindenyl, or fluorenyl may be independently selected from a group including halogen, hydrocarbyl (e.g.
• both Cp-ligands are indenyl moieties wherein each indenyl moiety bear one or two substituents as defined above. More preferably each Cp-ligand is an indenyl moiety bearing two substituents as defined above, with the proviso that the substituents are chosen in such are manner that both Cp-ligands are of different chemical structure, i.e. both Cp-ligands differ at least in one substituent bonded to the indenyl moiety, in particular differ in the substituent bonded to the five member ring of the indenyl moiety.
• both Cp are indenyl moieties wherein the indenyl moieties comprise at least at the five membered ring of the indenyl moiety, more preferably at 2-position, a substituent selected from the group consisting of alkyl, such as C 1 - to C 6 - alkyl, e.g. methyl, ethyl, isopropyl, and trialkyloxysiloxy, wherein each alkyl is independently selected from C 1 - to C 6 - alkyl, such as methyl or ethyl, with proviso that the indenyl moieties of both Cp chemically differ from each other, i.e. the indenyl moieties of both Cp comprise different substituents.
• alkyl such as C 1 - to C 6 - alkyl, e.g. methyl, ethyl, isopropyl, and trialkyloxysiloxy
• each alkyl is independently selected from C 1 - to C 6
• both Cp are indenyl moieties wherein the indenyl moieties comprise at least at the six membered ring of the indenyl moiety, more preferably at 4-position, a substituent selected from the group consisting of a C 6 - to C 20 - aromatic ring moiety, such as phenyl or naphthyl, preferably phenyl, which is optionally substituted with one or more substituents, such as C 1 - to C 6 - alkyl, and a heteroaromatic ring moiety, with proviso that the indenyl moieties of both Cp chemically differ from each other, i.e. the indenyl moieties of both Cp comprise different substituents.
• both Cp are indenyl moieties wherein the indenyl moieties comprise at the five membered ring of the indenyl moiety, more preferably at 2-position, a substituent and at the six membered ring of the indenyl moiety, more preferably at 4-position, a further substituent, wherein the substituent of the five membered ring is selected from the group consisting of alkyl, such as C 1 - to C 6 - alkyl, e.g.
• each alkyl is independently selected from C 1 - to C 6 - alkyl, such as methyl or ethyl
• the further substituent of the six membered ring is selected from the group consisting of a C 6 - to C 20 - aromatic ring moiety, such as phenyl or naphthyl, preferably phenyl, which is optionally substituted with one or more substituents, such as C 1 - to C 6 - alkyl, and a heteroaromatic ring moiety, with proviso that the indenyl moieties of both Cp chemically differ from each other, i.e.
• both Cp comprise different substituents. It is in particular preferred that both Cp are idenyl rings comprising two substituents each and differ in the substituents bonded to the five membered ring of the indenyl rings.
• R has the formula (II) -Y(R') 2 - (II) wherein Y is C, Si or Ge, and
• R' is C 1 - to C 20 - alkyl, C 6 - to C 12 - aryl, or C 7 - to C 12 - arylalkyl or trimethylsilyl.
• the bridge member R is typically placed at 1-position.
• the bridge member R may contain one or more bridge atoms selected from e.g. C, Si and/or Ge, preferably from C and/or Si.
• One preferable bridge R is - Si(R') 2 -, wherein R' is selected independently from one or more of e.g.
• alkyl as such or as part of arylalkyl is preferably C 1 - to C 6 - alkyl, such as ethyl or methyl, preferably methyl, and aryl is preferably phenyl.
• the bridge -Si(R') 2 - is preferably e.g.
• the asymmetric catalyst i.e. the asymmetric metallocene
• the asymmetric metallocene is defined by the formula (III) (Cp) 2 R 1 ZrCl 2 (III) wherein both Cp coordinate to M and are selected from the group consisting of unsubstituted cyclopentadienyl, unsubstituted indenyl, unsubstituted tetrahydroindenyl, unsubstituted fluorenyl, substituted cyclopentadienyl, substituted indenyl, substituted tetrahydroindenyl, and substituted fluorenyl, with the proviso that both Cp-ligands are of different chemical structure, and R is a bridging group linking two ligands L, wherein R is defined by the formula (II) -Y(R') 2 - (II) wherein Y is C, Si or Ge, and R' is C 1 - to C 20 - alkyl
• the asymmetric catalyst is defined by the formula (III), wherein both Cp are selected from the group consisting of substituted cyclopentadienyl, substituted indenyl, substituted tetrahydroindenyl, and substituted fluorenyl.
• the asymmetric catalyst is defined by the formula (III), wherein both Cp are selected from the group consisting of substituted cyclopentadienyl, substituted indenyl, substituted tetrahydroindenyl, and substituted fluorenyl with the proviso that both Cp-ligands differ in the substituents, i.e. the substituents as defined above, bonded to cyclopentadienyl, indenyl, tetrahydroindenyl, or fluorenyl.
• the asymmetric catalyst is defined by the formula (III), wherein both Cp are indenyl and both indenyl differ in one substituent, i.e. in a substituent as defined above bonded to the five member ring of indenyl.
• the asymmetric catalyst is a non-silica supported catalyst as defined above, in particular a metallocene catalyst as defined above.
• the asymmetric catalyst is dimethylsilyl [(2-methyl-(4'- tert- butyl)-4-phenyl-indenyl) (2-isopropyl-(4'- tert- butyl)-4-phenyl-indenyl)]zirconium dichloride (IUPAC: dimethylsilandiyl [(2-methyl-(4'- tert- butyl)-4-phenyl-indenyl)(2-isopropyl-(4'- tert- butyl)-4-phenyl-indenyl)]zirconium dichloride). More preferred said asymmetric catalyst is not silica supported.
• the asymmetric catalyst system is obtained by the emulsion solidification technology as described in WO 03/051934 .
• the asymmetric catalyst is preferably in the form of solid catalyst particles, obtainable by a process comprising the steps of
• a solvent more preferably an organic solvent, is used to form said solution.
• the organic solvent is selected from the group consisting of a linear alkane, cyclic alkane, linear alkene, cyclic alkene, aromatic hydrocarbon and halogen-containing hydrocarbon.
• the immiscible solvent forming the continuous phase is an inert solvent, more preferably the immiscible solvent comprises a fluorinated organic solvent and/or a functionalized derivative thereof, still more preferably the immiscible solvent comprises a semi-, highly- or perfluorinated hydrocarbon and/or a functionalized derivative thereof.
• said immiscible solvent comprises a perfluorohydrocarbon or a functionalized derivative thereof, preferably C 3 -to C 30 - perfluoroalkanes, C 3 - to C 30 - alkenes or C 3 - to C 30 - cycloalkanes, more preferred C 4 - to C 10 - perfluoro-alkanes, C 4 - to C 10 - alkenes or C 4 - to C 10 - cycloalkanes, particularly preferred perfluorohexane, perfluoroheptane, perfluorooctane or perfluoro (methylcyclohexane) or a mixture thereof.
• a perfluorohydrocarbon or a functionalized derivative thereof preferably C 3 -to C 30 - perfluoroalkanes, C 3 - to C 30 - alkenes or C 3 - to C 30 - cycloalkanes, more preferred C 4 - to C
• the emulsion comprising said continuous phase and said dispersed phase is a bi- or multiphasic system as known in the art.
• An emulsifier may be used for forming the emulsion. After the formation of the emulsion system, said catalyst is formed in situ from catalyst components in said solution.
• the emulsifying agent may be any suitable agent which contributes to the formation and/or stabilization of the emulsion and which does not have any adverse effect on the catalytic activity of the catalyst.
• the emulsifying agent may e.g. be a surfactant based on hydrocarbons optionally interrupted with (B) heteroatom(s), preferably halogenated hydrocarbons optionally having a functional group, preferably semi-, highly- or perfluorinated hydrocarbons as known in the art.
• the emulsifying agent may be prepared during the emulsion preparation, e.g. by reacting a surfactant precursor with a compound of the catalyst solution.
• Said surfactant precursor may be a halogenated hydrocarbon with at least one functional group, e.g. a highly fluorinated C 1 - to C 30 - alcohol, which reacts e.g. with a cocatalyst component, such as aluminoxane.
• a halogenated hydrocarbon with at least one functional group e.g. a highly fluorinated C 1 - to C 30 - alcohol, which reacts e.g. with a cocatalyst component, such as aluminoxane.
• any solidification method can be used for forming the solid particles from the dispersed droplets.
• the solidification is effected by a temperature change treatment.
• the emulsion subjected to gradual temperature change of up to 10 °C/min, preferably 0.5 to 6 °C/min and more preferably 1 to 5 °C/min.
• the emulsion is subjected to a temperature change of more than 40°C, preferably more than 50 °C within less than 10 seconds, preferably less than 6 seconds.
• the recovered particles preferably have an average size range of 5 to 200 ⁇ m, more preferably 10 to 100 ⁇ m.
• the form of solidified particles have preferably a spherical shape, a predetermined particles size distribution and a surface area as mentioned above of preferably of less than 25 m 2 /g, still more preferably of less than 20 m 2 /g, yet more preferably of less than 15 m 2 /g, yet still more preferably of less than 10 m 2 /g and most preferably of less than 5 m 2 /g, wherein said particles are obtained by the process as described above.
• the catalyst system may further comprise an activator as a cocatalyst, as described in WO 03/051934 .
• cocatalysts for metallocenes and non-metallocenes are the aluminoxanes, in particular the C 1 - to C 10 -alkylaluminoxanes, most particularly methylaluminoxane (MAO).
• aluminoxanes can be used as the sole cocatalyst or together with other cocatalyst(s).
• other cation complex forming catalysts activators can be used. Said activators are commercially available or can be prepared according to the prior art literature.
• aluminoxane cocatalysts are described inter alia in WO 94/28034 . These are linear or cyclic oligomers of having up to 40, preferably 3 to 20, -(AI(R"')O)- repeat units (wherein R"' is hydrogen, C 1 -to C 10 -alkyl (preferably methyl) or C 6 - to C 18 -aryl or mixtures thereof).
• the use and amounts of such activators are within the skills of an expert in the field.
• 5:1 to 1:5, preferably 2:1 to 1:2, such as 1:1, ratio of the transition metal to boron activator may be used.
• the amount of Al, provided by aluminoxane can be chosen to provide a molar ratio of Al:transition metal e.g. in the range of 1 to 10 000, suitably 5 to 8000, preferably 10 to 7000, e.g. 100 to 4000, such as 1000 to 3000.
• the ratio is preferably below 500.
• the quantity of cocatalyst to be employed in the catalyst of the invention is thus variable, and depends on the conditions and the particular transition metal compound chosen in a manner well known to a person skilled in the art.
• any additional components to be contained in the solution comprising the organotransition compound may be added to said solution before or, alternatively, after the dispersing step.
• the process for producing polypropylene (B) using the above defined metallocene catalyst is preferably a multi-stage process.
• Multistage processes include also bulk/gas phase reactors known as multizone gas phase reactors for producing multimodal propylene polymer.
• a preferred multistage process is a "loop-gas phase"-process, such as developed by Borealis A/S, Denmark (known as BORSTAR® technology) described e.g. in patent literature, such as in EP 0 887 379 or in WO 92/12182 .
• Multimodal polymers can be produced according to several processes which are described, e.g. in WO 92/12182 , EP 0 887 379 and WO 97/22633 .
• a multimodal polypropylene (B) is produced preferably in a multi-stage process in a multi-stage reaction sequence as described in WO 92/12182 .
• a suitable polymer usable as component (B) and a process for its preparation is described in EP 1 892 264 .
• Component (C) is a linear low density ethylene homo- or copolymer (C) which has been produced with a single-site catalyst, preferably, component (C) is a linear low density ethylene compolymer.
• Polyethylenes produced with a single-site catalyst usually have a narrower molecular weight distribution (MWD) and are substantially linear, i.e. do not contain long chain branches. If an ethylene copolymer is produced with a single-site catalyst the comonomers are more statistically distributed in the polymer chain. Thus, polyethylenes differ in their chemical structure from polyetylenes produced with Ziegler-Natta catalyst which produce a broader MWD and a less statistical comonomer distribution and from polyethylenes produced by a radical initiated high pressure process which have a large amount of long chain branches.
• MWD molecular weight distribution
• component (C) has an MFR 2 measured according to ISO 1133 at 190°C and under a load of 2.16 kg, of at least 0.01 g/10 min, more preferably of at least 0.1 g/10 min, even more preferably of at least 0.5 g/10 min and most preferably of at least 0.9 g/10 min.
• component (C) has an MFR 2 measured according to ISO 1133 at 190°C and under a load of 2.16 kg, of not more than 10.0 g/10 min, more preferably of not more than 5.0 g/10 min, even more preferably of not more than 3.5 g/10 min and most preferably of not more than 2.0 g/10 min.
• component (C) has a density of at least 900 kg/m 3 , more preferably of at least 910 kg/m 3 and most preferably of at least 915 kg/m 3 .
• component (C) has a density of not more than 940 kg/m 3 , more preferably of not more than 935 kg/m 3 and most preferably of not more than 930 kg/m 3 .
• component (C) has a melting point of at least 110°C, more preferably of at least 115°C.
• component (C) is an ethylene copolymer.
• said copolymer has a comonomer content of not more than 15.0 wt.%, more preferably of not more than 10.0 wt.% and most preferably of not more than 7.0 wt.% based on component (C).
• said copolymer has a comonomer content of at least 1.0 wt.%, more preferably of least 2.0 wt.% and most preferably of least 3.0 wt.%
• the comonomers used for the production of component (C) may be selected from but are not limited to C 3 - to C 20 -alpha-olefins.
• the use of one or more of C 3 - to C 20 -alpha-olefins is preferred, even more preferred is the use of one or more of C 3 - to C 15 -alpha-olefins, even more preferred is the use of one or more of C 4 - to C 10 -alpha-olefins, e . g . 1-butene, 1-hexene, 1-octene or a mixture thereof, and most preferred is the use of a C 4 - to C 6 -alpha-olefin, e . g . 1-hexene.
• Component (C) may be unimodal or multimodal. In case component (C) is multimodal it is preferably bimodal.
• metallocene catalysts are especially preferred. Suitable catalysts and their preparation are described in EP 260 130 , WO/97/28170 , WO/98/46616 , WO/98/49208 , WO/99/12981 , WO/99/19335 , EP 836 608 , WO/98/56831 , WO/00/34341 , EP 423 101 , EP 537 130 and WO/00/40620 .
• a hafnium metallocene catalyst e.g. bis(n-butylcyclopentadienyl)hafnium dichloride or bis(n-butylcyclopentadienyl)hafnium dibenzyl is used.
• Suitable polymers to be used as component (C) and their preparation are described in EP 1 472 298 and WO/06/045501 .
• the polypropylene composition has an MFR 2 measured according to ISO 1133, at 230°C and under a load of 2.16 kg, of at least 0.1 g/10 min, more preferably of at least 0.5 g/10 min and most preferably of at least 1.0 g/10 min.
• the polypropylene composition has an MFR 2 measured according to ISO 1133, at 230°C and under a load of 2.16 kg, of not more than 20 g/10 min, more preferably of not more than 10 g/10 min and most preferably of not more than 20 g/10 min.
• the polypropylene composition has a melting point of at least 150 °C, more preferably of at least 155 °C and most preferably of at least 160 °C.
• the polypropylene composition of the invention may further contain various additives, such as miscible thermoplastics, antioxidants, UV-stabilizers, lubricants, nucleating agents, fillers, colouring agents, processing aids and foaming agents which can be added to the composition before, during or after the blending or later during the production of finished or semi-finished articles, e.g. films in an amount of up to 5.0 wt%, preferably up to 3.0 wt% based on the total polymer composition.
• additives such as miscible thermoplastics, antioxidants, UV-stabilizers, lubricants, nucleating agents, fillers, colouring agents, processing aids and foaming agents which can be added to the composition before, during or after the blending or later during the production of finished or semi-finished articles, e.g. films in an amount of up to 5.0 wt%, preferably up to 3.0 wt% based on the total polymer composition.
• the invention is furthermore directed to a process for producing the polypropylene composition according to the invention.
• the inventive polypropylene composition can be produced by any suitable melt mixing process at temperatures above the melting point of the respective polypropylene composition.
• Typical devices for performing said melt mixing process are twin screw extruders, single screw extruders optionally combined with static mixers, chamber kneaders like Farell kneaders and reciprocating co-kneaders like Buss co-kneaders.
• the melt mixing process is carried out in a twin screw extruder with high intensity mixing segments and preferably at a temperature of 170 to 270 °C, more preferably of 180 to 250 °C.
• inventive polypropylene composition may also be compounded just prior being further processed into the desired article, i.e. the polymer is directly fed from the melt mixing process in molten state to the next processing step, e.g. a film blowing machine.
• Said melt mixing process can be carried out as described above, preferably in a single screw extruder, optionally comprising a static mixer, is used, preferably at a temperature from 170 to 270 °C, more preferably from 180 to 250 °C.
• the invention is furthermore directed to an article comprising the polypropylene composition according to the invention.
• said article is and/or comprises a blown film.
• Possible articles for which the inventive blown film and or the polypropylene composition can be used are lamination films, general packaging films, like bread bags, pouches and medical/hygienic films.
• said blown film is manufactured by extrusion of the polypropylene composition as defined herein by conventional blown film extrusion, i.e. the polypropylene composition is extruded through a die, preferably circular die, followed by "bubble-like" expansion.
• the blown films according to this invention are preferably produced on a single screw extruder with a barrel diameter of 70 mm and a round-section die of 200 mm with 1 mm die gap in combination with a monolip cooling ring and internal bubble cooling (IBC).
• Melt temperature is preferably 210 °C in the die; the temperature of the cooling air is kept preferably at 15 °C and the blow up ratio (BUR) is preferably 3:1.
• BUR blow up ratio
• a film thickness of 50 ⁇ m is adjusted through the ratio between extruder output, takeoff speed and BUR.
• the blown film has a haze of not more than 20 %, more preferably of not more than 15 % and most preferably of not more than 12.5 %.
• the tensile modulus (md) of the blown film is at least 1300 MPa, more preferably is at least 1400 MPa and most preferably is at least 1420 MPa.
• the tensile stress at yield (md) of the blown film is at least 30.0 MPa, more preferably is at least 32.0 MPa and most preferably is at least 33.2 MPa.
• the tensile strain at yield (md) of the blown film is not more than 16.0 %, more preferably is not more than 15.5 %.
• the tensile strength (md) of the blown film is at least 60 MPa, more preferably is at least 63 MPa.
• the tensile strain at break (md) of the blown film is not more than 680 %, more preferably is not more than 660 %.
• the tensile modulus (td) of the blown film is at least 1100 MPa, more preferably is at least 1180 MPa.
• the tensile stress at yield (td) of the blown film is at least 25.0 MPa, more preferably is at least 27.0 MPa.
• the tensile strain at yield (td) of the blown film is not more than 10.0 %, more preferably is not more than 9.0 %.
• the tensile strength (td) of the blown film is at least 30 MPa, more preferably is at least 33 MPa.
• the tensile strain at break (td) of the blown film is not more than 800 %, more preferably is not more than 700 %.
• the blown film has been produced on a commercial blown-film line Alpine 35, using a screw with compression and metering zone with temperature settings 180/200/220/220/220 °C and a initial screw speed of 80 rpm.
• the bubble has been stretched with a blow up ratio of 2 and winded up with 10.4 m/min.
• the screw speed of the Alpine 35 was more than 90 rpm, more preferably at least 95 rpm and most preferably at least 100 rpm when processing the polypropylene composition according to the invention to obtain a film with the properties as defined above.
• the invention is furthermore directed to the use of the polypropylene composition according to the invention for the production of an article, preferably for the production of a blown film.
• the branching index g' defines the degree of branching and correlates with the amount of branches of a polymer.
• a low g'-value is an indicator for a high branched polymer. In other words, if the g'-value decreases, the branching of the polypropylene increases.
• the intrinsic viscosity needed for determining the branching index g' is measured according to DIN ISO 1628/1, October 1999 (in Decalin at 135 °C).
• Particle size distribution is measured via Coulter Counter LS 200 at room temperature with n-heptane as medium.
• a Waters Alliance GPCV 2000 instrument equipped with refractive index detector and online viscosimeter was used with 3 x TSK-gel columns (GMHXL-HT) from TosoHaas and 1,2,4-trichlorobenzene (TCB, stabilized with 200 mg/l 2,6-di- tert- butyl-4-methyl-phenol) as solvent at 145 °C and at a constant flow rate of 1 ml/min. 216.5 ⁇ l of sample solution were injected per analysis.
• the column set was calibrated using relative calibration with 19 narrow MWD polystyrene (PS) standards in the range of 0.5 kg/mol to 11 500 kg/mol and a set of well characterised broad polypropylene standards. All samples were prepared by dissolving 5-10 mg of polymer in 10 ml (at 160 °C) of stabilized TCB (same as mobile phase) and keeping for 3 hours with continuous shaking prior sampling in into the GPC instrument.
• PS polystyrene
• the solution from the first 100 ml vessel is evaporated in nitrogen flow and the residue is dried under vacuum at 90 °C until constant weight is reached.
• the content of xylene hot insolubles is determined by extracting 1 g of finely cut polymer sample with 500 ml xylene in a Soxleth extractor for 48 hours at the boiling temperature. The remaining solid amount is dried at 90 °C and weighed for determining the insolubles amount.
• the cross-linking degree of the polyethylene component (B) is calculated by normalizing the weight percentage of xylene hot insolubles to the weight percentage of component (B).
• FTIR Fourier transform infrared spectroscopy
• Film thickness was 50 ⁇ m and the film was produced as follows.
• the pelletized materials have been used for film blowing at a commercial blown-film line Alpine 35, using a screw with compression and metering zone with temperature settings 180/200/220/220/220°C and a initial screw speed as given in the table below.
• the bubble has been stretched with a blow up ratio of 2 and winded up with 10.4 m/min.
• the films from IE1 and IE2 behave significantly different to the known polymers.
• the film is much easier to process.
• the blown film had a thickness of 50 ⁇ m.
• the melt temperature was 221°C.
• Film thickness was 50 ⁇ m and the film was produced as described under i) above.
• the melt flow rate is determined according to ISO 1133 and is indicated in g/10 min.
• the MFR is an indication of the melt viscosity of the polymer.
• the MFR is determined at 190°C for PE and at 230 °C for PP.
• the load under which the melt flow rate is determined is usually indicated as a subscript, for instance MFR 2 is measured under 2.16 kg load, MFR 5 is measured under 5 kg load or MFR 21 is measured under 21.6 kg load.
• Density of the polymers was measured according to ISO 1183/D on compression molded specimens.
• Charpy impact strength was determined according to ISO 179-1eA:2000 on V-notched samples having a size of 80x10x4 mm 3 at +23 °C (Charpy impact strength (+23°C)) and -20 °C (Charpy impact strength (-20°C)).
• the base radius was 0.25 mm.
• test specimens were prepared by injection molding according to ISO 1873-2.
• a high pressure capillary rheometer (Type: Rheograph 2002, Göttfert Maschinenstoff-Prufmaschinen GmbH, Buchen, Germany) was used to extrudate polymer strands which were stretched by means of a Rheotens melt tension apparatus (Type: 7197, Göttfert Maschinenstoff-Prüfmaschinen GmbH).
• the haul-off force F in dependence of draw-down velocity v is recorded.
• the test procedure is performed in a standard climatized room with controlled room temperature of 23 °C.
• the temperature of the rheometer was set at 200 °C.
• a capillary of 20 mm length and 1 mm diameter was used.
• the acceleration of the wheels of the Rheotens was set to 120 mm/s 2 for all the measurements.
• the diameter of the barrel was 12 mm.
• the polymer was allowed to melt for 4 minutes.
• the extrusion rate of the strand is 0.0217 mm/s (equivalent to an apparent shear rate of 25s -1 ).
• the length of the spinning line was 104 mm.
• the haul-off force F (in N) is measured against the stretch ratio ⁇ . This way a curve is obtained.
• the maximum force before rupture of the polymer strand is called "Melt Strength".
• the copolymer had an ethylene content of 3.6 mol% and a xylene soluble fraction (EPR content) at RT of 14 wt.%.
• the MFR 2 (230°C; 2.16 kg) is 3.0 g/10 min.
• the density was 905 kg/m 3 and the melting point 167°C.
• the Charpy notched impact strength according to ISO 179-1eA:2000 at 23°C was 29.8 kJ/m 2 .
• the weight average particle size of the disperse phase was 0.35 ⁇ m.
• the polymer had a density of 905 kg/m 3 , a melting point of 165°C.
• the MFR 2 (230°C; 2.16 kg) is 6.0 g/10 min.
• the melt strength was 11.5 cN at a maximum speed of 242 mm/s and a the branching index g' was 0.64.
• the ethylene copolymer had an MFR 2 (190°C; 2.16 kg) of 1.3 g/10 min, a density of 922 kg/m 3 , a content of 1-hexene of 5.1 wt.% and a melting point of 118°C.
• the ethylene homopolymer had an MFR 2 (190°C; 2.16 kg) of 0.75 g/10 min, a density of 923 kg/m 3 and a melting point of 112°C.
• the polypropylene compositions have been produced by melt mixing at 200-250 °C in a twin screw extruder ZSK57 (Coperion W&P, Germany), cooled in a water bath and strand pelletized. The resulting granules were fed into the film blowing machine (Alpine 35).
• the pelletized materials have been used for film blowing at a commercial blown-film line Alpine 35, using a screw with compression and metering zone with temperature settings 180/200/220/220/220°C and a initial screw speed as given in the table below.
• the bubble has been stretched with a blow up ratio of 2 and winded up with 10.4 m/min.
• the films from IE1 and IE2 behave significantly different to the known polymers.
• the film is much easier to process.
• the blown film had a thickness of 50 ⁇ m.
• the melt temperature was 221°C for each polymer composition.
• table 1 IE 1 IE 2 CE 3 CE 4 CE 5 CE 6 CE 7 P1 [wt.%] 85 75 85 75 95 90 100 P2 [wt.%] 10 10 10 P3 [wt.%] 5 15 5 10 P4 [wt.%] 5 15 Optics haze % 9.6 11.9 14.9 24.6 8.9 9.2 8.3

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